Hecuba Keeps Late Season Surface Action in the Cards
Late summer can coincide with waning dry fly fishing on many rivers in the Rocky Mountain West. For other trout streams, however, it’s just kicking into gear. Much of this is due to emergences of important aquatic insects like Claassenia (typically referred to as the mutant stonefly) and mahogany duns. These heralded hatches keep “in-the-know” dry fly junkies happy well into autumn. Another bug can produce the same excitement when they appear around the same time.
Timpanoga Hecuba hecuba is and often neglected mayfly in the world of trout fishing. Despite its coverage in Hafele and Hughes’ Western Mayfly Hatches (Frank Amato Publications) and Knopp and Cormier’s Mayflies (Graycliff Publishing), few fly fishers have actually heard of the Hecuba.
The common name for Hecuba - the great blue-winged red quill or the great red quill - is rarely used amongst anglers who know about them. Most refer to it by its scientific handle – Hecuba. It is significant on Yellowstone area waters like the Snake River in Wyoming and streams of the Lamar River drainage in Yellowstone National Park, including Slough and Soda Butte creeks. There are also noted emergences in eastern Oregon and Southern Colorado. It emerges on most water it inhabits from the beginning of August until early October.
Hecuba is a big mayfly. Most duns are 15mm to 17mm in length with some specimens going 19mm to 20mm. I have heard it described fittingly as a “drake on steroids”. In fact, many fly fishers misidentify Hecuba as a brown drake or gray drake upon seeing it for the first time. They are crawler nymphs, but their body shape and behavior is reminiscent of clinger nymphs. They are strikingly flat and seem to cling tied to river cobble and other subsurface structure. One bug collecting angler I now in Wyoming describes having to almost peel specimens off river rock with a knife in order to examine them closely.
Hecuba favors streams with moderate currents, yet they are also abundant on large river systems with gradients of 12 feet per mile or more. On these waters, Hecuba tends to cluster in side channels where currents are typically slower than those in main channels.
Cloudy, wet weather can bring Hecubas out in force. This is something I experience with most mayflies. Mayfly adults are dry-bodied bug. They die from dehydration if they are not consumed by fish and birds first. Because of this, it seems appropriate that cool, cloudy weather with precipitation produces mayfly hatches. I see this with everything from pale morning duns to blue-winged olives. But by far, the most intense hatches I have fished during such weather events have been Hecuba. Emergences can be prolific and, at times, long in duration. Their large bodies are matched by equally large wings. Those wings are the indelible impression of a big hatch. Some I have fished with describe the event as an invasion of sailboats.
Riffles and seams are obvious targets when an emergence is underway. However, nothing is more important than fishing side channels, particularly near their confluence with faster main channels. When a hatch occurs, emergers and duns will come pouring out of side channels and into main channels where they are devoured by waiting trout. I have sat on these confluences when a hatch is occurring and witnessed several dozen rises over a period of just a couple of minutes.
Hecuba is not as widely dispersed as more popular western mayflies like PMDs, blue-winged olives, and green drakes. In many places where they are present, hatches are sporadic. No doubt this is a reason so many fly fishers have little knowledge of them. Where robust populations exist, local anglers tend to be big fans. This is certainly the case in the Yellowstone Region where I call home. Streams like the South Fork of the Snake and the Teton River in Idaho are, for the most part, devoid of Hecuba. Yet less than a half hour drive across the border is the upper Snake River in Wyoming’s, which has a well-known emergence. During the month of August, nymphs become active and can easily be found clinging to the bottom and sides of wading footwear. The first emergences generally start the last week of the month and can continue into the first half of October if the weather is right. Fly shops in the area stock up on drake-like imitations leading up to the first week of September, only to watch their bins dwindle to nothing, even after several restockings. Early autumn is perhaps the most popular time of the year to fish the Snake River. Hecuba is a big reason why.
Standard larva patterns like Hare’s Ear Nymphs and Copper Johns (in copper) are commonly used as sub-surface imitations for Hecuba. However, fly fishers can have significantly more success with surface imitations when a hatch is underway. Almost anything you use as a brown drake or gray drake imitation will work as a Hecuba. The Ribbed Parawulff Hares Ear is a longtime favorite of those who target this hatch. The Parachute Hares Ear is a standby pattern as well.
I personally prefer emerger imitations when Hecuba is hatching and will fish them right through an entire emergence. Some of the most productive patterns are those tied on a heavy gauge curved nymph hook. Such a hook allows the shuck and abdomen to hang below the surface film, similar to the Klinkhammer and Bob Quigley’s Film Critic. When fishing high gradient streams, I will often incorporate a small piece of notched foam tied into the parachute post between the hackle and the abdomen. This provides buoyancy to a fly designed to hang partly below the surface.
No matter the pattern you use, remember that Hecuba is one of the largest mayflies in North America. Go with those that are between #10 and #12 in size. And as I mentioned above, be prepared to fish them when clouds and rain are in the forecast.